This invention relates to a method of sensitizing zinc oxide with a dye.
Many types of photosensitive materials utilizing zinc oxide sensitized with a dye have been manufactured and are available on the market. However, their durability is low, that is they can withstand repeated use of at most 100 times. Also their moisture resistance and recovery from light irradiation hysteresis are not always satisfactory. In spite of these defects they have been used for a long time because zinc oxide is inexpensive and easy to sensitize.
Due to poor durability, in recent years zinc oxide has been replaced by selenium type photosensitive materials. The largest factor that governs the durability is the loss of the sensitizing effect of the dye which is termed conduction deterioration. Since the theory of conduction deterioration is still not established, no efficient measure for preventing this effect has yet been proposed.